Rolling mill for producing longitudinally tapered sheet,plate and sections

ABSTRACT

A ROLLING MILL FOR ROLLING LONGITUDINALLY TAPERED SHEET, PLATE AND SECTIONS WHEREBY THE WORK ROLLS ARE ECCENTRIC HOLLOW SLEEVES. THESE ECCENTRIC HOLLOW SLEEVES HAVE A CYLINDRICAL INNER SURFACE AND A TAPERED ROLL WALL THICKNESS AROUND THE PERIPHERY OF THE ROLL FOR ROLLING TAPERED SHEETS AND PLATES AD A TAPERED RECESS IN A CONSTANT THICKNESS ROLL WALL FOR ROLLING TAPERED SECTIONS. THE ROLLS ARE DRIVEN AND SUPPORTED BY SMALLER RLLS POSITIONED WITHIN THE HOLLOW WORK ROLLS.

Sept. 20, 1971 c. P. MUELLER ETAL 3,605,184

ROLLING MILL FOR PRODUCING LONGITUDINALLY TAPERED SHEET, PLATE AND SECTIONS 3 Sheets-Sheet 1 Filed March 14, 1969 //V VE N TORS. Charles Mueller William A. Mc/Ve/sh BY WM M AM wu b THE/R ATTORNEYS C. P. MUELLER EI'AL ROLLING MILL FOR PRODUCING LONGI'I'UDINALLY 'I'APERED SHEET. PLATE AND SECTIONS 3 Sheets-Sheet 2 Sept. 20, 1971 Filed March 14, 1969 L A l5 f T l6 B 1 0 Ill INVENTORS. Charles P. Mueller William A. McNeish B WM AMAMM 5' T HE If? ATTORNEYS P 1971 c. P. MUELLER ETAL 3,605,184

FOR PRODUCI LONGITUDI LY TAP ROLLING M NG ERED HEET, PLATE AND SECTION Filed March 14, 1969 3 Sheets-Sheet 3 INVENTORS CHARLES P. MUELLER WILLIAM A. McNEISH wi /3W4 Mia M United States Patent 3,605,184 ROLLING MILL FOR PRODUCING LONGITUDI- NALLY TAPERED SHEET, PLATE AND SECTIONS Charles P. Mueller, Upper St. Clair Township, Allegheny County, Pa., and William A. McNeish, New Hartford, N.Y., assignors to Cyclops Corporation, Universal- Cyclops Specialty Steel Division, Pittsburgh, Pa.

Filed Mar. 14, 1969, Ser. No. 807,309 Int. Cl. 132% 7/10 US. Cl. 18-9 Claims ABSTRACT OF THE DISCLOSURE A rolling mill for rolling longitudinally tapered sheet, plate and sections whereby the work rolls are eccentric hollow sleeves. These eccentric hollow sleeves have a cylindrical inner surface and a tapered roll wall thickness around the periphery of the roll for rolling tapered sheets and plates and a tapered recess in a constant thickness roll wall for rolling tapered sections. The rolls are driven and supported by smaller rolls positioned within the hollow work rolls.

Our invention relates to a rolling mill for producing longitudinally tapered sheet, plate and sections. More particularly, it relates to the eccentric hollow work rolls which produce these tapered products.

There is, and has been for a long time, a demand for extremely long longitudinally tapered metal sheet and plate. Typical of this demand are the requirements of the aerospace industry where lon-g tubular products are frequently required wherein one end of the tube requires properties substantially different than those of the other end due to varying support requirements. Another typical example of a tapered section requirement is the wing of an aeroplane wherein the portion of the wing attached to the fuselage must contain a heavier cross section than the wing tip. In addition to the demand for tapered sheet or plate for such applications, there is a demand for tapered sections to act as support members. As used herein, the term section includes all the shape products such as standard and geometric shapes, as well as other sections, and the term product refers to these longitudinally tapered sheets, plates and sections. The term plate includes in addition to recognized plate gauges, metal sheets of all thicknesses.

There are a number of methods and devices presently used to produce these tapered products. The most common means of producing tapered products has been by machining. For example, in the aerospace industry large multiple head milling machines, often 100 feet in length, are utilized. These milling machines actually machine the desired tapered contour of a wing from a plate of uniform thickness. This procedure is very expensive and in some instances yields of only 10% to are achieved.

Another and more recent innovation in the manufacture of tapered products is the use of chemical milling techniques whereby different portions of a product to be tapered are exposed for different times to a chemical which continually removes the surface of the product at a known rate. This can be accomplished, for example, by drawing a product through a chemical milling unit at a predetermined, increasing or decreasing rate of speed. While chemical milling techniques have improved yields over normal milling operations, the operation is cumbersome and costly. Therefore, it remains a time consuming and expensive step of manufacture.

Small, tapered parts have been produced by machining the shape into the roll, but this is not amenable to the type of tapered products envisioned by this invention because of the limitations in length that the process imposes.

Our invention produces longitudinally tapered products of sufiicient length to enable manufacturers to make large parts such as aeroplane wings with a minimum, if any, amount of milling. Our invention is also amenable to producing tapered sections having lengths comparable to the tapered sheet and plate for use as support members and the like.

Thus, the use of these tapered products eliminates most yield losses associated with the various machining operations conducted heretofore and, therefore, appreciably reduces the cost of producing large articles Where longitudinal tapering is required.

Because of the availability of large tapered sheet, plate and sections, parts which could have utilized the inherent advantages of tapered dimensions, but for the prohibitive machining costs, will become a reality.

Our invention is a rolling mill for rolling longitudinally tapered products wherein the work rolls are hollow eccentric sleeves or uniform thickness sleeves having tapered grooves which are driven and supported by drive and idler rolls positioned within and adjacent the sleeves.

In the accompanying drawings, we have shown various embodiments of our invention in which:

FIG. 1 is a section through a pair of tapered work rolls rotating about a horizontal axis;

FIG. 2 is a section through a pair of tapered work rolls which are being fed at the roll nip by a hopper of powdered metal;

FIG. 3 is a section through a pair of work rolls showing a T-section grooved into the respective rolls;

FIG. 4 is a blown-up section through the eccentric grooves of two work rolls for producing a tapered section;

FIG. 5 is a section through a Turks Head configuration showing horizontal and vertical work rolls for longitudinally tapering a T-section along its width and height dimensions; and

FIG. 6 is a section through a pair of tapered rolls having an intermediate hollow sleeve.

The simplest arrangement for rolling tapered sheet and plate is shown in FIG. 1 and consists of two hollow work rolls, generally 1 and 2, having parallel horizontal rolling axes. Each roll 1, and 2, consists of a sleeve, 3 and 4, the outer surface of which represents the roll surface which contacts the sheet or plate to be rolled. These sleeves, 3 and 4, have cylindrical inner surfaces 11 and 12. The work rolls 1 and 2 are driven by drive rolls 5 and 6, respectively, which are positioned adjacent the inner surfaces 11 and 12, respectively, of the sleeves 3 and 4, respectively. The sleeves 3 and 4 are also supported by support (idler) rolls 7 and 8, respectively. These support rolls 7 and 8 may be either fixed or movable to accommodate different size sleeves. Each roll, therefore, con sists of an outer sleeve, supported and driven by rolls adjacent the inner surface of the sleeves. As in conventional rolling, it may be desirable for a given rolling mill to drive only one of the work rolls as opposed to both of them.

The thicknesses a and a, respectively, of the sleeves 3 and 4 are tapered, diminishing in thickness from starting points 9 and 10, respectively, around the periphery thereof to points 13 and 14, respectively, which are spaced from but close to the original starting point. The sleeve thickness is also referred to hereinafter as the roll wall thickness. This tapered sleeve is obtainable, for example, by machining the taper over the length of a starting plate and then roll forming and welding the plate to form the outer sleeve. Of course, as will be recognized by those skilled in the art, there are a number of ways to obtain this roll configuration. The balance of the periphery of the roll series as a fill-in section for the overshoot from the rolling 3 operation. Therefore, the tapered sleeve actually represents an eccentric roll surface.

It is apparent that a plate or sheet passing through the rolls 1 and 2 will have a longitudinal taper corresponding to the taper of the sleeve thickness about the periphery of the roll. The length of plate or Sheet which can be tapered is limited by the circuference of the roll. In other words, a tapered starting plate 60 feet long, when roll formed and welded to form the eccentric sleeve for the work roll, will taper a sheet or plate approximately the same length. It would be highly impractical to produce a solid eccentric roll of sufficient size to produce a 60 foot tapered plate or a sheet for a part such as an aeroplane wing. It would actually take a solid roll having a diameter in excess of 19 feet to accomplish this.

Prior to rolling, the starting points 9 and of each roll 1 and 2, respectively, should be in common alignment to fall on an arbitrary line connecting the rolling axes of the two rolls so that one complete revolution of each roll 1 and 2 will impart the taper of the rolls to a sheet or plate having a length up to the circumference of the rolls. A mechanical or electrical stop (not shown) can be employed to stop the rolls after one complete revolution to always maintain the proper alignment of the rolls prior to rolling the next sheet or plate. Of course, it is not absolutely necessary to position the starting points as just described. For example, where the length of the starting stock is substantially less than the circumference of the rolls, the starting points should be commonly positioned on other respective rolls, relative to each other, but need not be aligned to fall on an arbitrary line connecting the rolling axes.

The rolling of tapered sheet or plate can be carried out by multiple passes as well as a single pass. For example, a relatively short thick section of metal stock can be passed through the mill a number of times in the same direction to produce a final product having a length up to the length of the work rolls and a taper equivalent to the taper of the roll wall thickness about the periphery of the roll. Where multiple passes are employed, the rolls can be reversible. That is, the roll wall thickness can increase instead of diminish as shown in FIG. 1. In other words, the roll wall thickness increases in thickness around the periphery of the roll from the starting point of each roll.

A further embodimentof our invention involves using the tapered roll concept in conjunction with known powder metallurgy techniques to produce a tapered compacted strip from a powdered metal starting material (see FIG. 2). Rolling mills having large diameter sleeves for compacting metal powder into a compacted strip are well known to those skilled in the art as shown in British Pat. No. 896,668. However, by employing our special rolls, one can obtain a tapered compacted strip.

In this embodiment, a set of tapered rolls 1 and 2, constructed, supported and driven the same as rolls 1 and 2 of FIG. 1, and having parallel-horizontal rolling axes are positioned side by side in slightly spaced apart relationship to define a roll nip 55. The roll nip is positioned below a hopper 50 containing a powdered metal 52. At the aligned starting points 9 and 10', respectively, of each roll 1 and 2', gates 53 and 54, respectively, hold the powder at the roll nip 55 prior to initiating the roll ing. The opening 51 of hopper 50 is synchronized with the roll speeds and the space between the rolls at the roll nip 54 to properly control the flow rate of the metal powder 52.

One complete revolution of the rolls 1 and 2' with metal powder being fed to the roll nip 55 at the proper flow rate results in a longitudinally tapered compacted metal strip.

When rolling a tapered strip from a powdered metal, the rolls are reversible in that the starting point can be either the alignment of the thickest or thinnest wall thick ness of the respective rolls and the only necessary adjustment is the proper control of the flow rate into the roll nip. In addition, because of the ease of formation of a compacted strip from a powder, the taper of the rolls can be increased or decreased freely about the periphery of each roll to produce a variety of longitudinal tapers.

The same concept of tapered rolls as applied to powder metallurgy is also applicable to the continuous casting of liquid metals. Of course, the rolls have to be watercooled and have to be assembled in line with a tundish to receive the liquid metal. A gate arrangement or a dummy slab positioned at the roll nip controls the initial surge of molten metal just prior to rolling. The various forms of oscillation employed with a casting mold could be incorporated into the rolls themselves. As in the case of rolling tapered products from powder, the rolls can be reversible in that the thickest or thinnest section can be rolled first by merely controlling the feed rate of the liquid metal.

An intermediate concentric hollow sleeve of constant wall thickness can be employed with the tapered outer sleeves to minimize outer sleeve thickness and facilitate handling, storage, etc., see FIG. 6. Outer tapered sleeve 3 and 4" are mounted, by standard mountings such as frictional or key mountings, to inner sleeves 24' and 25 of constant thickness, respectively. Sleeves 24 and 25 are in contact with the drive rolls 5" and 6," respectively and the various idler rolls (not shown).

The same concept of large diameter sleeves can be employed to roll longitudinally tapered sections. The only difference is that the sleeve thickness is constant and the grooves or recesses in the rolls are tapered to obtain the desired longitudinally tapered sections. For example, a T-section formed of two grooved rolls can be longitudinally tapered along various dimensions (see FIG. 3). In FIG. 3, upper roll 17 contains the groove 15 for the web portion of the T and lower roll 16 contains the groove for the base portion 16 of the T. By tapering the depth of the groove 15 around the periphery of the roll, the height of the resultant web, shown by C, will diminish over the length of the T-section while the width of the web, shown by A, can be held constant. At the same time, the height, shown by D, of the base can be tapered into the groove 16 while holding the width dimension, shown by B, constant. The result is a rolled T-section having a tapered web and base along its length, yet having a uniform web thickness and base width.

The rolls 17 and 18 are driven by drive rolls 21 and 22, respectively, adjacent the inner surfaces of the roll sleeves (see FIG. 4). Although not shown, support or idler rolls are also employed within the hollow sleeves.

The rolls 17 and 18 of FIG. 4, each consist of two separate sleeves, i.e., inner sleeve 24 and outer sleeve 26 for roll 17 and inner sleeve 25 and outer sleeve 27 for roll 18. The outer sleeves 26 and 27 of rolls 17 and 18, respectively, contain the tapered grooves 15 and 16, respectively. The outer sleeves are concentrically mounted adjacent the inner sleeves and held thereon by any of the various means known to those skilled in the art, such as frictional or key mountings. The advantage of employing two concentric sleeves is the ease of interchanging relatively thin grooved sleeves, as compared to a single thickness sleeve containing the groove which increases the total weight which must be handled each time and increases the size and volume of rolls which must be kept on hand for vrious sections.

It is readily apparent that the roll sleeves can contain a number of grooves as is typical of many rolls currently employed to roll various sections. In addition, a train of synchronized roll stands can be employed to produce the same tapered sections.

Tapered grooves or recesses in a roll sleeve can also be utilized in a typical Turks Head configuration for rolling various section (see FIG. 5). In FIG. 5, rolls 30, 31, having parallel-horizontal rolling axes and tapered sleeves 38 and 39, respectively, are driven by drive rolls 34 and 35, respectively Rolls 30 and 31 are similar to rolls 1 and 2 of FIG. 1 but could, of course, have concentric sleeves as shown for rolls 17 and 18 of FIG. 4.

Rolls 32 and 33 having parallel-vertical axes and roll sleeves 40 and 41, respectively, are driven by rolls 36 and 37, respectively. Roll sleeves 40 and 41 are each recessed to contain one-half of the web and base of the T-section 45. Roll sleeves 40 and 41 have tapering roll thicknesses, as shown by dimension M, to impart a taper to the width of the web and base of the T-section 45. The sides of roll sleeves 40 and 41 are also tapered, as shown by dimen sion N, to cooperate with the taper of rolls 30 and 31, respectively. In other words, when the thickest section of sleeves 38 and 39 is in contact with the section being rolled, the thinnest section of sleeves 40 and 41 is contacting said shape.

One complete synchronized revolution from a starting position of all four rolls produces a T-section having a length equal to the circumference of the rolls, which is tapered along that length both as to the height and width of the web and base. As in the case of rolling tapered plates, multiple passes can be employed to produce the desired tapered shape.

While we have shown and described preferred embodiments of our invention, it may be otherwise embodied within the scope of the appended claims.

We claim:

1. A rolling mill adapted for producing longitudinally tapered plates comprising: i

(A) two hollow work rolls positioned with their rolling axes parallel, each roll having (i) an inner roll surface defining a cylinder;

(ii) an outer roll surface for contacting the plate;

and

(iii) a roll wall unidirectionally changing in thickness from a first point on the outer roll surface, around the periphery of said roll and to a second point spaced from but adjacent said first point, each of said first points being similarly positioned relative to each other prior to rolling;

(B) at least one support roll positioned within each hollow work roll and in contact with said inner surface; and

(C) at least one drive roll positioned within at least one hollow work roll and in contact with said inner surface whereby rotation of said work rolls imparts a taper to said plate substantially equal to the taper of the roll wall.

2. The rolling mill of claim 1 wherein at least one of the hollow work rolls is concentrically mounted on an intermediate hollow sleeve of constant wall thickness, said intermediate sleeve having an inner surface contacting the drive and support rolls.

3.. The rolling mill of claim 1 wherein one drive roll is positioned within each hollow work roll.

4. The rolling mill of claim 1 wherein said Work rolls are positioned side by side so as to define a nip between them, and a hopper containing a powdered metal is positioned above said nip, whereby said hopper continuously feeds the metal powder to said nip at a predetermined flow rate and a solid compacted plate having a taper substantially equal to the roll walls is formed as the work rolls rotate.

5. A rolling mill adapted for producing longitudinally tapered plates comprising:

(A) at least one pair of work rolls positioned with the rolling axis of each roll of the pair parallel to the rolling axis of the other roll of the pair, each roll of the pair having (i) an inner roll surface defining a cylinder;

(ii) an outer roll surface for contacting the plate;

and

(iii) a roll wall unidirectionally changing in thickness from a first point on the outer roll surface, around the periphery of said roll and to a second point spaced from but adjacent said first point, each of said first points being similarly positioned relative to each other prior to rolling;

(B) at least one support roll positioned Within each hollow work roll and in contact with said inner surface; and

(C) at least one drive roll positioned within at least one hollow work roll of each pair and in contact with said inner surface.

References Cited UNITED STATES PATENTS 3,245,114 4/1966 Ready et al 189 J. SPENCER OVERHOLSER, Primary Examiner D. S. SAFRAN, Assistant Examiner US. Cl. X.R. 1819RR 

